Tyre

ABSTRACT

An outer shoulder land region includes first shoulder lateral grooves each extending axially inwardly from an outer tread ground contact edge to have a first inner end in the tyre axial direction within the outer shoulder land region, first outer shoulder lateral sipes each connecting between the first inner end and an outer shoulder main groove, and second outer shoulder lateral sipes each extending axially inwardly from the outer tread ground contact edge to have a second inner end positioned on an axially outer side of the first inner ends. An outer middle land region includes outer middle lateral sipes each smoothly connected with the respective first outer shoulder lateral sipe with the outer shoulder main groove therebetween. Each of the outer middle lateral sipes connects between the outer shoulder main groove and an outer crown main groove and has a third inner end within the outer middle land region.

TECHNICAL FIELD

The present invention relates to a tyre having improved drainageperformance while maintaining steering stability performance and noiseperformance.

BACKGROUND ART

As disclosed in Japanese Unexamined Patent Application Publication No.2013-100020 (Patent Literature 1), various kinds of tyres havingimproved drainage performance have been proposed conventionally.

SUMMARY OF THE INVENTION

However, even with the technology shown in Patent Literature 1, it isnot easy to realize all of the steering stability performance, the noiseperformance, and the drainage performance at a high level, therefore,there has been a demand for further improvement.

The present invention was made in view of the above, and a primaryobject thereof is to provide a tyre having improved drainage performancewhile maintaining the steering stability performance and the noiseperformance.

In one aspect of the present invention, a tyre comprises a tread portioncomprising a first tread ground contact edge positioned on one side of atyre equator, a second tread ground contact edge positioned on the otherside of the tyre equator, first shoulder main groove extendingcontinuously in a tyre circumferential direction on a side of the firsttread ground contact edge, a first crown main groove extendingcontinuously in the tyre circumferential direction between the firstshoulder main groove and the tyre equator, a first middle land regiondefined between the first shoulder main groove and the first crown maingroove, and a first shoulder land region defined between the first treadground contact edge and the first shoulder main groove, wherein thefirst shoulder land region is provided with a plurality of firstshoulder lateral grooves each extending inwardly in a tyre axialdirection from the first tread ground contact edge to have a first innerend in the tyre axial direction within the first shoulder land region,first shoulder lateral sipes each connecting between the first inner endof a respective one of the first shoulder lateral grooves and the firstshoulder main groove, and a plurality of second shoulder lateral sipeseach extending inwardly in the tyre axial direction from the first treadground contact edge to have a second inner end on an outer side in thetyre axial direction of the first inner end, the first middle landregion is provided with a plurality of middle lateral sipes eachsmoothly connected with a respective one of the first shoulder lateralsipes with the first shoulder main groove therebetween, and the middlelateral sipes include first middle lateral sipes each connecting betweenthe first shoulder main groove and the first crown main groove andsecond middle lateral sipes each having a third inner end within thefirst middle land region.

In another aspect of the invention, it is preferred that each of thesecond shoulder lateral sipes is arranged between the first shoulderlateral grooves adjacent to each other in the tyre circumferentialdirection.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the first shoulder lateral grooves is ina range of from 50% to 75% of a length in the tyre axial direction ofthe first shoulder land region.

In another aspect of the invention, it is preferred that an angle ofeach of the first shoulder lateral grooves with respect to the tyreaxial direction is in a range of from 5 to 12 degrees.

In another aspect of the invention, it is preferred that an angle ofeach of the middle lateral sipes with respect to the tyre axialdirection is in a range of from 5 to 35 degrees.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the second shoulder lateral sipes is ina range of from 30% to 75% of a length in the tyre axial direction ofthe first shoulder land region.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the second middle lateral sipes is in arange of from 35% to 70% of a length in the tyre axial direction of thefirst middle land region.

In another aspect of the invention, it is preferred that the treadportion further comprises a second shoulder main groove extendingcontinuously in the tyre circumferential direction on a side of thesecond tread ground contact edge, a second crown main groove extendingcontinuously in the tyre circumferential direction between the secondshoulder main groove and the tyre equator, and a second middle landregion defined between the second shoulder main groove and the secondcrown main groove, wherein the second middle land region is providedwith a plurality of first middle lateral grooves each extending inwardlyin the tyre axial direction from the second shoulder main groove to havea fourth inner end in the tyre axial direction within the second middleland region, third middle lateral sipes each connecting between thefourth inner end of a respective one of the first middle lateral groovesand the second crown main groove, a plurality of second middle lateralgrooves each extending inwardly in the tyre axial direction from thesecond shoulder main groove to have a fifth inner end in the tyre axialdirection within the second middle land region, and fourth middlelateral sipes each extending inwardly in the tyre axial direction fromthe fifth inner end of a respective one of the second middle lateralgrooves to have a sixth inner end in the tyre axial direction within thesecond middle land region, and a length in the tyre axial direction ofeach of the second middle lateral grooves is 50% or more of a length inthe tyre axial direction of the second middle land region.

In another aspect of the invention, it is preferred that each of thesecond middle lateral grooves are provided between the first middlelateral grooves adjacent to each other in the tyre circumferentialdirection.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the first middle lateral grooves is 50%or more of a length in the tyre axial direction of the second middleland region.

In another aspect of the invention, it is preferred that each of fifthmiddle lateral sipes is provided between a respective one of pairs ofthe first inner middle lateral groove and the second inner middlelateral groove adjacent to each other in the tyre circumferentialdirection, and each of the fifth middle lateral sipes extends inwardlyin the tyre axial direction from the second shoulder main groove to havea seventh inner end in the tyre axial direction within the second middleland region.

In another aspect of the invention, it is preferred that the firstmiddle lateral grooves and the second middle lateral grooves areinclined in the same direction with respect to the tyre axial direction.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the first middle lateral grooves is in arange of from 60% to 80% of a length in the tyre axial direction of thesecond middle land region.

In another aspect of the invention, it is preferred that the treadportion is provided with a second shoulder land region defined betweenthe second tread ground contact edge and the second shoulder maingroove, and the second shoulder land region is provided with a pluralityof second shoulder lateral grooves each extending inwardly in the tyreaxial direction from the second tread ground contact edge to have aeighth inner end in the tyre axial direction within the second shoulderland region, and third shoulder lateral sipes each connecting betweenthe eighth inner end of a respective one of the second shoulder lateralgrooves and the second shoulder main groove.

In another aspect of the invention, it is preferred that a length in thetyre axial direction of each of the second shoulder lateral grooves is50% or more of a length in the tyre axial direction of the secondshoulder land region.

In another aspect of the invention, it is preferred that an angle ofeach of the second shoulder lateral grooves with respect to the tyreaxial direction is in a range of from 5 to 12 degrees.

In another aspect of the invention, it is preferred that the treadportion is provided with a plurality of fourth shoulder lateral sipeseach connecting between the second tread ground contact edge and thesecond shoulder main groove, and each of the fourth shoulder lateralsipes is arranged between a respective pair of the second shoulderlateral grooves adjacent to each other in the tyre circumferentialdirection

In another aspect of the invention, it is preferred that a groove widthof the first shoulder main groove is smaller than a groove width of thefirst crown main groove.

In another aspect of the invention, it is preferred that a groove widthof the first shoulder main groove is smaller than a groove width of thesecond shoulder main groove and a groove width of the second crown maingroove.

In another aspect of the invention, it is preferred that, when the tyreis mounted on a vehicle, the first tread ground contact edge is an outertread ground contact edge positioned on an outer side of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a development view of a tread portion of a tyre as anembodiment of the present invention.

FIG. 2A is a cross-sectional view taken along A-A line of FIG. 1.

FIG. 2B is a cross-sectional view taken along B-B line of FIG. 1.

FIG. 3 is an enlarged development view of a middle land region and ashoulder land region positioned on an outer side of a vehicle of FIG. 1.

FIG. 4 is an enlarged development view of a middle land region and ashoulder land region positioned on an inner side of the vehicle of FIG.1.

FIG. 5 is an enlarged development view of a crown land region of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will now be described inconjunction with accompanying drawings.

FIG. 1 is a development view of a tread portion 2 of a tyre according toan embodiment of the present invention. As shown in FIG. 1, the tyre inthis embodiment is suitably used as a pneumatic tyre for a passengercar, for example, but it is not limited thereto.

The tyre in this embodiment is provided with an asymmetric tread patternwhose position when mounted on a vehicle is specified. The mountingposition of the tyre on a vehicle is indicated by letters and the likeon at least one of sidewall portions (not shown), for example.

The tread portion 2 includes a tread ground contact edge TE1 positionedon one side of a tyre equator (C) and a tread ground contact edge TE2positioned on the other side of the tyre equator (C).

The tread ground contact edges TE1 and TE2 means outermost tread groundcontact edges in a tyre axial direction when the tyre in a standardstate is in contact with a flat surface with zero camber angles by beingloaded with a standard tyre load. Here, the standard state is a state inwhich the tyre is mounted on a standard rim (not shown), inflated to astandard tyre inner pressure, and loaded with no tyre load. Hereinafter,dimensions and the like of various parts of the tyre are those measuredunder the standard state, unless otherwise noted.

The “standard rim” is a wheel rim specified for the concerned tyre by astandard included in a standardization system on which the tyre isbased, for example, the “normal wheel rim” in JATMA, “Design Rim” inTRA, and “Measuring Rim” in ETRTO.

The “standard tyre inner pressure” is air pressure specified for theconcerned tyre by a standard included in a standardization system onwhich the tyre is based, for example, the “maximum air pressure” inJATMA, maximum value listed in the “TIRE LOAD LIMITS AT VARIOUS COLDINFLATION PRESSURES” table in TRA, and “INFLATION PRESSURE” in ETRTO.When the tyre is for a passenger car, the standard inner pressure is 180kPa, for example.

The “standard tyre load” is a tyre load specified for the concerned tyreby a standard included in a standardization system on which the tyre isbased, for example, the “maximum load capacity” in JATMA, maximum valuelisted in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” tablein TRA, and “LOAD CAPACITY” in ETRTO. When the tyre is for a passengercar, the standard tyre load is a load equivalent to 88% of the aboveload.

In this embodiment, it is preferred that the tyre is used such that,when the tyre is mounted on a vehicle, the tread ground contact edge TE1is an outer tread ground contact edge positioned on an outer side of thevehicle. However, the tyre may be used such that when the tyre ismounted on a vehicle, the tread ground contact edge TE1 is an innertread ground contact edge positioned on an inner side of the vehicle. Acase will be described below in which the tread ground contact edge TE1is the outer tread ground contact edge and the tread ground contact edgeTE2 is the inner tread ground contact edge.

The tread portion 2 includes an outer shoulder main groove 5 (a firstshoulder main groove) extending continuously in the tyre circumferentialdirection on a side of the outer tread ground contact edge TE1 (a firsttread ground contact edge), and an outer crown main groove 3 (a firstcrown main groove) extending continuously in the tyre circumferentialdirection between the outer shoulder main groove 5 and the tyre equator(C). The tread portion 2 includes an inner shoulder main groove 6 (asecond shoulder main groove) extending continuously in the tyrecircumferential direction on a side of the inner tread ground contactedge TE2 (a second tread ground contact edge), and an inner crown maingroove 4 (a second crown main groove) extending continuously in the tyrecircumferential direction between the in r shoulder main groove 6 andthe tyre equator (C).

It is possible that a groove width W1 of the outer crown main groove 3,a groove width W2 of the inner crown main groove 4, a groove width W3 ofthe outer shoulder main grooves 5, and a groove width W4 of the innershoulder main grooves 6 are arbitrarily determined according to thecustom. In a case of the pneumatic tyre in this embodiment for apassenger car, it is preferred that each of the groove widths W1, W2,W3, and W4 are in a range of from 4.0% to 8.5% of a tread groundcontacting width TW, for example.

The tread ground contacting width TW is a distance in the tyre axialdirection between the tread ground contact edges TE1 and TE2 when thetyre in the standard state is in contact with a flat surface with zerocamber angles by being loaded with the standard tyre load.

When any one of the groove widths W1, W2, W3, and W4 is less than 4.0%of the tread ground contacting width TW, it is possible that thedrainage performance is affected. On the other hand, when any one of thegroove widths W1, W2, W3, and W4 is more than 8.5% of the tread groundcontacting width TW, a rubber volume of the tread portion 2 isdecreased, therefore, it is possible that anti-wear performance isaffected.

FIG. 2A is a cross-sectional view of the tread portion 2 taken along A-Aline of FIG. 1. FIG. 2B is a cross-sectional view of the tread portion 2taken along B-B line of FIG. 1. As shown in FIG. 2A and 2B, it ispossible that a depth D1 of the outer crown main groove 3, a depth D2 ofthe inner crown main groove 4, a depth D3 of the outer shoulder maingroove 5, and a depth D4 of the inner shoulder main groove 6 arearbitrarily determined according to the custom. In a case of thepneumatic tyre in this embodiment for a passenger car, it is preferredthat each of the depths D1, D2, D3, and D4 are in a range of from 5 to10 mm, for example.

When any one of the depths D1, D2, D3, and D4 is less than 5 mm, it ispossible that the drainage performance is affected. On the other hand,when any one of the depths D1, D2, D3, and D4 is more than 10 mm,rigidity of the tread portion 2 is insufficient, therefore, it ispossible that the steering stability performance is affected.

The tread portion 2 has a crown land region 10 defined between the outercrown main groove 3 and the inner crown main groove 4. The tread portion2 has an outer middle land region 11 (first middle land region) definedbetween the outer crown main groove 3 and the outer shoulder main groove5. The tread portion 2 has an outer shoulder land region 13 (firstshoulder land region) defined between the outer shoulder main groove 5and the outer tread ground contact edge TE1. The tread portion 2 has aninner middle land region 12 (second middle land region) defined betweenthe inner crown main groove 4 and the inner shoulder main groove 6. Thetread portion 2 has an inner shoulder land region 14 (second shoulderland region) defined between the inner shoulder main groove 6 and theinner tread ground contact edge TE2.

FIG. 3 shows the outer middle land region 11 and the outer shoulder landregion 13.

The outer shoulder land region 13 is provided with a plurality of outershoulder lateral grooves 51 (first shoulder lateral grooves), aplurality of first outer shoulder lateral sipes 52 (first shoulderlateral sipes), and a plurality of second outer shoulder lateral sipes53 (second shoulder lateral sipes).

Each of the outer shoulder lateral grooves 51 extends inwardly in thetyre axial direction from the outer tread ground contact edge TE1 tohave a first inner end (51 i) in the tyre axial direction terminatingwithin the outer shoulder land region 13. Each of the outer shoulderlateral grooves 51 extends obliquely with respect to the tyre axialdirection in a curved manner. By the outer shoulder lateral grooves 51,the drainage performance of the outer shoulder land region 13 isimproved. The outer shoulder lateral grooves 51 terminate within theouter shoulder land region 13, therefore, the noise performance of thetread portion 2 is improved and the rigidity of the outer shoulder landregion 13 is increased, thereby, the steering stability performance isimproved.

Each of the first outer shoulder lateral sipes 52 extends so as toconnect between the first inner end (51 i) of a respective one of theouter shoulder lateral grooves 51 and the outer shoulder main groove 5.Each of the first outer shoulder lateral sipes 52 is connected with arespective one of the outer shoulder lateral grooves 51 and extendsobliquely in the same direction as the outer shoulder lateral grooves 51in a curved manner.

Each of the second outer shoulder lateral sipes 53 extends inwardly inthe tyre axial direction from the outer tread ground contact edge TE1 tohave a second inner end (53 i) terminating at a position on an outerside in the tyre axial direction of the first inner ends (51 i). Each ofthe second outer shoulder lateral sipes 53 extends parallel with theouter shoulder lateral grooves 51, that is at equal intervals in thetyre circumferential direction, and obliquely in the same direction asthe outer shoulder lateral grooves 51 in a curved manner.

By the first outer shoulder lateral sipes 52 and the second outershoulder lateral sipes 53, the drainage performance of the outershoulder land region 13 is further improved. Furthermore, the firstouter shoulder lateral sipes 52 and the second outer shoulder lateralsipes 53 are closed by high ground contact pressure on a groundcontacting surface. Thereby, it is possible that the drainageperformance of the outer shoulder land region 13 is easily improvedwhile suppressing deterioration of the noise performance and thesteering stability performance.

In particular, the first outer shoulder lateral sipes 52 each connectingbetween a respective one of the outer shoulder lateral grooves 51 andthe outer shoulder main groove 5 easily improve the drainage performanceof the outer shoulder land region 13. On the other hand, by the secondouter shoulder lateral sipes 53 terminating within the outer shoulderland region 13, continuity in the tyre circumferential direction of theouter shoulder land region 13 is maintained. Thereby, the noiseperformance of the tread portion 2 is easily improved and the rigidityof the outer shoulder land region 13 is easily increased, therefore, thesteering stability performance is improved.

The outer middle land region 11 is provided with a plurality of outermiddle lateral sipes 31 and 32 (middle lateral sipes) each extendinginwardly in the tyre axial direction from the outer shoulder main groove5. Each of the outer middle lateral sipes 31 and 32 is smoothlyconnected with a respective one of the first outer shoulder lateralsipes 52 with the outer shoulder main groove 5 therebetween. Theexpression that each of the outer middle lateral sipes 31 and 32 issmoothly connected with a respective one of the first outer shoulderlateral sipes 52 with the outer shoulder main groove 5 therebetweenmeans that the outer middle lateral sipes 31 and 32 are at least in apositional relation with the first outer shoulder lateral sipes 52 inwhich the outer middle lateral sipes 31 and 32 are inclined in the samedirection as the first outer shoulder lateral sipes 52 and an imaginaryextended line obtained by extending each of the first outer shoulderlateral sipes 52 inwardly in the tyre axial direction and an imaginaryextended line obtained by extending a respective one of the outer middlelateral sipes 31 and 32 outwardly in the tyre axial direction overlapeach other or are slightly displaced from each other in the tyrecircumferential direction. It is preferred that an amount of thedisplacement in the tyre circumferential direction is 2 mm or less, forexample. Each of the first outer shoulder lateral sipes 52 and arespective one of the outer middle lateral sipes 31 and 32 which aresmoothly connected with each other with the outer shoulder main groove 5therebetween function as one continuous sipe, therefore, the drainageperformance of the outer middle land region 11 and the outer shoulderland region 13 is easily improved.

By the outer middle lateral sipes 31 and 32 and the first outer shoulderlateral sipes 52 smoothly connected with each other as described above,the outer middle land region 11 and the outer shoulder land region 13deform in the same mode along the outer middle lateral sipes 31 and 32and the first outer shoulder lateral sipes 52. Thereby, for example,transient characteristics during cornering in which a center of theground contacting surface shifts from the outer middle land region 11 tothe outer shoulder land region 13 is improved, therefore, it is possiblethat excellent steering stability performance is obtained.

Each of the first outer middle lateral sipes 31 (first middle lateralsipes) extends so as to connect between the outer shoulder main groove 5and the outer crown main groove 3. By the first outer middle lateralsipes 31 configured as such, the outer shoulder main groove 5 and theouter crown main groove 3 are connected with each other, therefore, itis possible that the drainage performance of the outer middle landregion 11 is easily improved.

Each of the second outer middle lateral sipes 32 (second middle lateralsipes) has a third inner end (32 i) terminating within the outer middleland region 11. By the second outer middle lateral sipes 32 terminatingwithin the outer middle land region 11 as just described, the continuityin the tyre circumferential direction of the outer middle land region 11is maintained. Thereby, the noise performance of the tread portion 2 iseasily improved and the rigidity of the outer middle land region 11 iseasily increased, therefore, the steering stability performance isimproved.

The first outer middle lateral sipes 31 and the second outer middlelateral sipes 32 extend linearly or in an arc shape having a smallercurvature than the outer shoulder lateral grooves 51 and in parallelwith each other. The first outer middle lateral sipes 31 and the secondouter middle lateral sipes 32 configured as such contribute toimprovement of the drainage performance of the outer middle land region11.

Each of the second outer shoulder lateral sipes 53 is arranged between arespective pair of the outer shoulder lateral grooves 51 adjacent toeach other in the tyre circumferential direction. Thereby, the outershoulder lateral grooves 51 and the second outer shoulder lateral sipes53 are arranged alternately, one by one, in the tyre circumferentialdirection, therefore, the drainage performance, the noise performance,and the steering stability performance are improved in a good balance.

It is preferred that a length L1 in the tyre axial direction of each ofthe outer shoulder lateral grooves 51 is in a range of from 50% to 75%of a length L2 in the tyre axial direction of the outer shoulder landregion 13. When the length L1 is less than 50% of the length L2, it ispossible that the drainage performance is affected. When the length L1is more than 75% of the length L2, it is possible that the noiseperformance and the steering stability performance are affected.

It is preferred that an angle β1 of each of the first outer middlelateral sipes 31 with respect to the tyre axial direction is larger thanan angle α1 of each of the outer shoulder lateral grooves 51 withrespect to the tyre axial direction. The angle β1 is defined as an anglebetween the tyre axial direction and a straight line obtained byconnecting between an inner end and an outer end of each of the firstouter middle lateral sipes 31. The inner end is a point where a centerline of each of the first outer middle lateral sipes 31 is connectedwith the outer crown main groove 3 and the outer end is a point wherethe center line is connected with the outer shoulder main groove 5. Theangle α1 is defined as an angle between the tyre axial direction and astraight line obtained by connecting between a point where a center lineof each of the outer shoulder lateral grooves 51 intersects with theouter tread ground contact edge TE1 and the first inner end (51 i)thereof.

The angle β1 is set to be larger than the angle α1, therefore, it ispossible that excellent drainage performance is obtained in the outermiddle land region 11 during running straight. Further, it is possiblethat excellent drainage performance is obtained in the outer shoulderland region 13 during cornering.

It is preferred that an angle β2 of each of the second outer middlelateral sipes 32 with respect to the tyre axial direction is larger thanthe angle α1 of each of the outer shoulder lateral grooves 51 withrespect to the tyre axial direction. The angle β2 is defined as an anglebetween the tyre axial direction and a straight line obtained byconnecting between the third inner end (32 i) and an outer end of eachof the second outer middle lateral sipes 32. The outer end of each ofthe second outer middle lateral sipes 32 is where a center line thereofis connected with the outer shoulder main groove 5.

The angle β2 is set to be larger than the angle α1, therefore, it ispossible that excellent drainage performance is obtained in the outermiddle land region 11 during running straight. Further, it is possiblethat excellent drainage performance is obtained in the outer shoulderland region 13 during cornering.

It is preferred that the angle α1 of each of the outer shoulder lateralgrooves 51 with respect to the tyre axial direction is in a range offrom 5 to 12 degrees. When the angle α1 is less than 5 degrees, it ispossible that the drainage performance during running straight isaffected. When the angle α1 is more than 12 degrees, the rigidity in thetyre axial direction of the outer shoulder land region 13 is decreased,therefore, it is possible that the steering stability performance isaffected.

It is preferred that the angle β1 of each of the first outer middlelateral sipes 31 with respect to the tyre axial direction is in a rangeof from 5 to 35 degrees. When the angle β1 is less than 5 degrees, it ispossible that the drainage performance during running straight isaffected. When the angle β1 is more than 35 degrees, the rigidity in nthe tyre axial direction of the outer middle land region 11 isdecreased, therefore, it is possible that the steering stabilityperformance is affected.

It is preferred that the angle β2 of each of the second outer middlelateral sipes 32 with respect to the tyre axial direction is in a rangeof from 5 to 35 degrees. When the angle β2 is less than 5 degrees, it ispossible that the drainage performance during running straight isaffected. When the angle β2 is more than 35 degrees, the rigidity in thetyre axial direction of the outer middle land region 11 is decreased,therefore, it is possible that the steering stability performance isaffected.

The angle β1 and the angle β2 in this embodiment are set to be equal.Thereby, the rigidity of the outer middle land region 11 in the tyrecircumferential direction is made uniform, therefore, it is possiblethat excellent steering stability performance is obtained.

It is preferred that the angle α1 of each of the outer shoulder lateralgrooves 51 with respect to the tyre axial direction is set to be equalto an angle α2 of each of the second outer shoulder lateral sipes 53with respect to the tyre axial direction. The angle α2 is defined as anangle between the tyre axial direction and a straight line obtained byconnecting the second inner end (53 i) of each of the second outershoulder lateral sipes 53 and a point where a center line thereofintersects with the outer tread ground contact edge TE1. The angle α1and the angle α2 are set to be equal, therefore, the rigidity of theouter shoulder land region 13 in the tyre circumferential direction ismade uniform, thereby, it is possible that excellent steering stabilityperformance is obtained.

It is preferred that each of the outer shoulder lateral grooves 51 andthe second outer shoulder lateral sipes 53 extends outwardly in the tyreaxial direction beyond the outer tread ground contact edge TE1. Thereby,during cornering and the like, even when a ground contacting region ofthe outer shoulder land region 13 is expanded to the outer side in thetyre axial direction of the outer tread ground contact edge TE1,excellent drainage performance is maintained.

A length L3 in the tyre axial direction of each of the second outershoulder lateral sipes 53 is smaller than the length L2 in the tyreaxial direction of each of the outer shoulder land region 13. It ispreferred that the length L3 is in a range of from 30% to 70% of thelength L2. When the length L3 is less than 30% of the length L2, it ispossible that the drainage performance is affected. When the length L3is more than 70% of the length L2, it is possible that the noiseperformance and the steering stability performance are affected.

It is preferred that a length L4 in the tyre axial direction of each ofthe second outer middle lateral sipes 32 is in a range of from 35% to70% of a length L5 in the tyre axial direction of the outer middle landregion 11. When the length L4 is less than 35% of the length L5, it ispossible that the drainage performance is affected. When the length L4is more than 70% of the length L5, it is possible that the noiseperformance and the steering stability performance are affected.

It is preferred that the groove width W3 of the outer shoulder maingroove 5 is smaller than the groove width W1 of the outer crown maingroove 3. By the outer shoulder main groove 5 configured as such, it ispossible that excellent noise performance and excellent steeringstability performance are easily obtained. Note that, in thisembodiment, the outer shoulder lateral grooves 51, the first outershoulder lateral sipes 52, the second outer shoulder lateral sipes 53,the first outer middle lateral sipes 31, and the second outer middlelateral sipes 32 function organically, therefore, excellent drainageperformance is maintained even in the outer shoulder main groove 5described above.

It is preferred that the groove width W3 of the outer shoulder maingroove 5 is smaller than the groove width W4 of the inner shoulder maingroove 6. Further, it is preferred that the groove width W3 of the outershoulder main groove 5 is smaller than the groove width W2 of the innercrown main groove 4. By the outer shoulder main groove 5 configured assuch, similarly to the above, excellent noise performance and excellentsteering stability performance are easily obtained and excellentdrainage performance is maintained.

As shown in FIG. 2A, it is preferred that each of the first outer middlelateral sipes 31 has a depth larger at an inner end thereof in the tyreaxial direction than at an outer end thereof in the tyre axialdirection. Each of the inner end and the outer end of each of the firstouter middle lateral sipes 31 extends in the tyre axial direction at thesubstantially constant depth, respectively. The first outer middlelateral sipes 31 configured as such, together with the second outermiddle lateral sipes 32 having the third inner ends (32 i), improve thedrainage performance and the steering stability performance of the outermiddle land region 11 in a good balance.

It is preferred that each of the first outer shoulder lateral sipes 52has a depth larger at a center portion thereof in the tyre axialdirection than at an inner end and an outer end thereof in the tyreaxial direction. Each of the center portion, the inner end, and theouter end in the tyre axial direction of each of the first outershoulder lateral sipes 52 extends in the tyre axial direction at thesubstantially constant depth, respectively. The first outer shoulderlateral sipes 52 configured as such improve the drainage performance andthe steering stability performance of the outer shoulder land region 13in a good balance.

FIG. 4 shows the inner middle land region 12 and the inner shoulder landregion 14.

The inner middle land region 12 is provided with a plurality of firstinner middle lateral grooves 41 (first middle lateral grooves) and aplurality of second inner middle lateral grooves 43 (second middlelateral grooves). Each of the first inner middle lateral grooves 41extends inwardly in the tyre axial direction from the inner shouldermain groove 6 to have a fourth inner end (41 i) in the tyre axialdirection terminating within the inner middle land region 12. Each ofthe second inner middle lateral grooves 43 extends inwardly in the tyreaxial direction from the inner shoulder main groove 6 to have a fifthinner end (43 i) in the tyre axial direction terminating within theinner middle land region 12. By the first inner middle lateral grooves41 and the second inner middle lateral grooves 43 each connected withthe inner shoulder main groove 6, the drainage performance of the innermiddle land region 12 is improved.

In particular, it is preferred that a length L6 in the tyre axialdirection of each of the second inner middle lateral grooves 43 is 50%or more of a length L7 in the tyre axial direction of the inner middleland region 12. By the second inner middle lateral grooves 43 configuredas such, it is possible that the drainage performance of the innermiddle land region 12 is easily improved.

The first inner middle lateral grooves 41 and the second inner middlelateral grooves 43 terminate within the inner middle land region 12,therefore, the noise performance of the tread portion 2 is improved andthe rigidity of the inner middle land region 12 is increased, thereby,the steering stability performance is improved.

Each of the first inner middle lateral grooves 41 and the second innermiddle lateral grooves 43 extends linearly or in an arc shape having asmaller curvature than each of inner shoulder lateral grooves 61 and inparallel with each other. The first inner middle lateral grooves 41 andthe second inner middle lateral grooves 43 configured as such contributeto improvement of the drainage performance of the inner middle landregion 12.

The inner middle land region 12 is further provide with a plurality offirst inner middle lateral sipes 42 (third middle lateral sipes) and aplurality of second inner middle lateral sipes 44 (fourth middle lateralsipes). Each of the first inner middle lateral sipes 42 extends so as toconnect between the fourth inner end (41 i) of a respective one of thefirst inner middle lateral grooves 41 and the inner crown main groove 4.Each of the second inner middle lateral sipes 44 extends inwardly in thetyre axial direction from the fifth inner end (43 i) of a respective oneof the second inner middle lateral grooves 43 to have a sixth inner end(44 i) in the tyre axial direction terminating within the inner middleland region 12.

By the first inner middle lateral sipes 42 and the second inner middlelateral sipes 44, the drainage performance of the inner middle landregion 12 is further improved. Furthermore, the first inner middlelateral sipes 42 and the second inner middle lateral sipes 44 are closedby high ground contact pressure on the ground contacting surface.Thereby, it is possible that the drainage performance of the innermiddle land region 12 is easily improved while suppressing deteriorationof the noise performance and the steering stability performance.

In particular, the first inner middle lateral sipes 42 each connectingbetween the inner crown main groove 4 and a respective one of the firstinner middle lateral grooves 41 easily improve the drainage performanceof the inner middle land region 12. On the other hand, by the secondinner middle lateral sipes 44 terminating within the inner middle landregion 12, the continuity in the tyre circumferential direction of theinner middle land region 12 is maintained. Thereby, the noiseperformance of the tread portion 2 is easily improved and the rigidityof the inner middle land region 12 is easily increased, therefore, thesteering stability performance is improved.

Each of the second inner middle lateral grooves 43 is arranged betweenthe first inner middle lateral grooves 41 adjacent to each other in thetyre circumferential direction. Thereby, pairs of the first inner middlelateral groove 41 and the first inner middle lateral sipe 42 and pairsof the second inner middle lateral groove 43 and the second inner middlelateral sipe 44 are arranged alternately, one pair by one pair, in thetyre circumferential direction, therefore, the drainage performance, thenoise performance, and the steering stability performance are improvedin a good balance.

Each of the first inner middle lateral sipes 42 and the second innermiddle lateral sipes 44 extends linearly or in an arc shape having asmaller curvature than each of inner shoulder lateral grooves 61 and inparallel with each other. The first inner middle lateral sipes 42 andthe second inner middle lateral sipes 44 configured as such contributeto improvement of the drainage performance of the inner middle landregion 12.

It is preferred that a length L8 in the tyre axial direction of each ofthe first inner middle lateral grooves 41 is 50% or more of the lengthL7 in the tyre axial direction of the inner middle land region 12. Bythe first inner middle lateral grooves 41 configured as such, it ispossible that the drainage performance of the inner middle land region12 is easily improved.

It is preferred that third inner middle lateral sipes 45 (fifth middlelateral sipes) are each provided between a respective pair of the firstinner middle lateral groove 41 and the second inner middle lateralgroove 43 adjacent to each other in the tyre circumferential direction.In other words, one third inner middle lateral sipes 45, one first innermiddle lateral groove 41, one third inner middle lateral sipes 45, andone second inner middle lateral groove 43 are arranged in this orderrepeatedly in the tyre circumferential direction. Each of the thirdinner middle lateral sipes 45 extends inwardly in the tyre axialdirection from the inner shoulder main groove 6 to have a seventh innerend (45 i) in the tyre axial direction terminating within the innermiddle land region 12. By the provision of the third inner middlelateral sipes 45 in the inner middle land region 12, it is possible thatthe drainage performance of the inner middle land region 12 is furtherimproved.

It is preferred that the first inner middle lateral grooves 41 and thesecond inner middle lateral grooves 43 are inclined in the samedirection with respect to the tyre axial direction. By the first innermiddle lateral grooves 41 and the second inner middle lateral grooves 43which are inclined in the same direction, it is possible that thedrainage performance of the inner middle land region 12 is easilyimproved.

It is preferred that a first chamfered portion 46 is provided at acorner portion where each of the first inner middle lateral grooves 41intersects with the inner shoulder main groove 6 at an acute angle. Bythe first chamfered portions 46, flows of water flowing from the firstinner middle lateral grooves 41 to the inner shoulder main groove 6 arepromoted, therefore, it is possible that the drainage performance of theinner middle land region 12 is easily improved. Further, by the firstchamfered portions 46, stress at the corner portions is moderated.

It is preferred that a second chamfered portion 47 is provided at acorner portion where each of the second inner middle lateral grooves 43intersects with the inner shoulder main groove 6 at an acute angle. Bythe second chamfered portions 47, flows of water flowing from the secondinner middle lateral grooves 43 to the inner shoulder main groove 6 arepromoted, therefore, it is possible that the drainage performance of theinner middle land region 12 is easily improved. Further, by the secondchamfered portions 47, stress at the corner portions is moderated.

It is preferred that a length L9 in the tyre axial direction of each ofthe second inner middle lateral sipes 44 is in a range of from 15% to35% of the length L6 in the tyre axial direction of each of the secondinner middle lateral grooves 43. when the length L9 is less than 15% ofthe length L6, it is possible that the drainage performance is affected.When the length L9 is more than 35% of the length L6, it is possiblethat the noise performance and the steering stability performance areaffected.

It is preferred that the length L8 in the tyre axial direction of eachof the first inner middle lateral grooves 41 is in a range of from 60%to 80% of the length L7 in the tyre axial direction of the inner middleland region 12. When the length L8 is less than 60% of the length L7, itis possible that the drainage performance is affected. When the lengthL8 is more than 80% of the length L7, it is possible that the noiseperformance and the steering stability performance are affected.

The inner shoulder land region 14 in this embodiment is provided with aplurality of the inner shoulder lateral grooves 61 (second shoulderlateral grooves) and a plurality of first inner shoulder lateral sipes62 (third shoulder lateral sipes).

Each of the inner shoulder lateral grooves 61 extends inwardly in thetyre axial direction from the inner tread ground contact edge TE2 tohave an eighth inner end (61 i) in the tyre axial direction terminatingwithin the inner shoulder land region 14. Each of the inner shoulderlateral grooves 61 extends obliquely with respect to the tyre axialdirection in a curved manner. By the inner shoulder lateral grooves 61,the drainage performance of the inner shoulder land region 14 isimproved. The inner shoulder lateral grooves 61 terminate within theinner shoulder land region 14, therefore, the noise performance of thetread portion 2 is improved and the rigidity of the inner shoulder landregion 14 is increased, thereby, the steering stability performance isimproved.

Each of the first inner shoulder lateral sipes 62 extends so as toconnect between the eighth inner end (61 i) of a respective one of theinner shoulder lateral grooves 61 and the inner shoulder main groove 6.Each of the first inner shoulder lateral sipes 62 is connected with arespective one of the inner shoulder lateral grooves 61 and extendsobliquely in the same direction as the inner shoulder lateral grooves 61in a curved manner.

By the first inner shoulder lateral sipes 62 each connecting between arespective one of the inner shoulder lateral grooves 61 and the innershoulder main groove 6, the drainage performance of the inner shoulderland region 14 is further improved. Furthermore, the first innershoulder lateral sipes 62 are closed by high ground contact pressure onthe ground contacting surface. Thereby, it is possible that the drainageperformance of the inner shoulder land region 14 is easily improvedwhile suppressing deterioration of the noise performance and thesteering stability performance.

It is preferred that a length L10 in the tyre axial direction of each ofthe inner shoulder lateral grooves 61 is 50% or more of a length L11 inthe tyre axial direction of the inner shoulder land region 14. By theinner shoulder lateral grooves 61 configured as such, it is possiblethat excellent drainage performance is easily obtained.

It is preferred that each of the inner shoulder lateral grooves 61extends outwardly in the tyre axial direction beyond the inner treadground contact edge TE2. Thereby, during cornering and the like, evenwhen a ground contacting region of the inner shoulder land region 14 isexpanded to the outer side in the tyre axial direction of the innertread ground contact edge TE2, excellent drainage performance ismaintained.

It is preferred that the angle γ1 of each of the inner shoulder lateralgrooves 61 with respect to the tyre axial direction is in a range offrom 5 to 12 degrees. The angle γ1 is defined as an angle between thetyre axial direction and a straight line obtained by connecting betweena point where a center line of each of the inner shoulder lateralgrooves 61 intersects with the inner tread ground contact edge TE2 andthe eighth inner end (61 i) thereof. When the angle γ1 is less than 5degrees, it is possible that the drainage performance during runningstraight is affected, when the angle γ1 is more than 12 degrees, therigidity in the tyre axial direction of the inner shoulder land region14 is decreased, therefore, it is possible that the steering stabilityperformance is affected.

The inner shoulder land region 14 in this embodiment is provided with aplurality of second inner shoulder lateral sipes 63 (fourth shoulderlateral sipes). Each of the second inner shoulder lateral sipes 63extends so as to connect between the inner tread ground contact edge TE2and the inner shoulder main groove 6. By the second inner shoulderlateral sipes 63, the drainage performance of the outer shoulder landregion 13 is further improved. Furthermore, the second inner shoulderlateral sipes 63 are closed by high ground contact pressure on theground contacting surface. Thereby, it is possible that the drainageperformance of the outer shoulder land region 13 is easily improvedwhile suppressing deterioration of the noise performance and thesteering stability performance.

Each of the second inner shoulder lateral sipes 63 is arranged between arespective pair of the inner shoulder lateral grooves 61 adjacent toeach other in the tyre circumferential direction. Thereby, the innershoulder lateral grooves 61 and the second inner shoulder lateral sipes63 are arranged alternately in the tyre circumferential direction,therefore, the drainage performance, the noise performance, and thesteering stability performance are improved in a good balance.

As shown in FIG. 2A, it is preferred that each of the first inner middlelateral sipes 42 has a depth larger at a center portion thereof in thetyre axial direction than at an inner end and an outer end thereof inthe tyre axial direction. The first inner middle lateral sipes 42configured as such, together with the second inner middle lateral sipes44 having the sixth inner ends (44 i), improve the drainage performanceand the steering stability performance of the inner middle land region12 in a good balance.

It is preferred that each of the first inner shoulder lateral sipes 62has a depth larger at a center portion thereof in the tyre axialdirection than at an inner end and an outer end thereof in the tyreaxial direction. Each of the center portion, the inner end, and theouter end in the tyre axial direction of each of the first innershoulder lateral sipes 62 extends in the tyre axial direction at thesubstantially constant depth, respectively. The first inner shoulderlateral sipes 62 configured as such improve the drainage performance andthe steering stability performance of the inner shoulder land region 14in a good balance.

FIG. 5 shows the crown land region 10. The crown land region 10 isprovided with crown lateral sipes 21 and crown lateral grooves 22. Eachof the crown lateral sipes 21 extends inwardly in the tyre axialdirection from the outer crown main groove 3 to have an inner endterminating before reaching the tyre equator (C). The crown lateralsipes 21 are inclined in a direction opposite to the first outer middlelateral sipes 31. Each of the crown lateral grooves 22 extends inwardlyin the tyre axial direction from the inner crown main groove 4 to havean inner end terminating before reaching the tyre equator (C). The crownlateral grooves 22 are inclined in a direction opposite to the firstinner middle lateral grooves 41. The crown lateral sipes 21 and thecrown lateral grooves 22 are inclined in the same direction and extendin parallel with each other.

In the crown land region 10, by the provision of the crown lateral sipes21 on a side of the outer tread ground contact edge TE1 and the crownlateral grooves 22 on a side of the inner tread ground contact edge TE2,the rigidity of the crown land region 10 is easily increased on the sideof the outer tread ground contact edge TE1 and the drainage performanceof the crown land region 10 is easily improved on the side of the innertread ground contact edge TE2. Thereby, by using the outer tread groundcontact edge TE1 as the outer tread ground contact edge, it is possiblethat the drainage performance is easily improved while maintaining thesteering stability performance and the noise performance.

It is preferred that a third chamfered portion 23 is provided at acorner portion where each of the crown lateral grooves 22 intersectswith the inner crown main groove 4 at an acute angle. By the thirdchamfered portion 23, flows of water flowing from the crown lateralgrooves 22 to the inner crown main groove 4 are promoted, therefore, itis possible that the drainage performance of the crown land region 10 iseasily improved. Further, by the third chamfered portion 23, stress atthe corner portions is moderated.

While detailed description has been made of the tyre of the presentinvention, the present invention can be embodied in various formswithout being limited to the illustrated embodiment.

WORKING EXAMPLES (EXAMPLES)

Pneumatic tyres of size 215/60R16 having the basic tread pattern shownin FIG. 1 were made by way of test according to the specificationslisted in Table 1, and then the test tyres were tested for the drainageperformance, the noise performance, and the steering stabilityperformance. Reference 1 was a pneumatic tyre having the tread patterndisclosed in the Patent Literature 1. The test methods were as follows.

<Drainage Performance>

Each of the test tyres was mounted on a rim of 16×7.03 and mounted onall wheels of a test vehicle (FF car with displacement of 2500 cc) underthe condition of the tyre inner pressure of 250 kPa. While the testvehicle described above was driven on an asphalt road surface of a testcourse having a radius of 100 meters with a paddle having a depth of 5mm and a length of 20 meters, lateral acceleration (lateral G) of thefront wheels during running was measured and an average lateral G at thetime when the test vehicle was driven at a speed in a range of from 50to 80 km/h was calculated (lateral hydroplaning test). The test resultsare indicated by an index based on Example 1 being 100, wherein a largernumerical value is better.

<Noise Performance>

While the test vehicle was driven on a road noise measuring road (a roadhaving a rough asphalt surface) at a speed of 60 km/h, the in-car noisewas sampled at a position in the vicinity of the driver's window-sideear, and the sound pressure level was measured. The test results areindicated by an index based on the value of the Example 1 being 100,wherein a larger numerical value is better.

<Steering Stability Performance>

While a driver drove the test vehicle described above on a dry asphaltroad surface of a test course with the driver being the only member onthe test vehicle, characteristics relating to grip performance, steeringresponse, and responsiveness were evaluated by the driver's feeling. Thetest results are indicated by an evaluation point based on the Example 1being 100, wherein the larger the numerical value, the better thesteering stability performance is.

TABLE 1 Ref. 1 Ref. 2 Ex. 1 Ex. 2 Ex. 3 Outer shoulder lateral groovesPresent Present Present Present Present First outer shoulder sipesAbsent Present Present Present Present Second outer shoulder sipesAbsent Present Present Present Present Outer middle lateral groovesPresent Absent Absent Absent Absent First outer middle sipes AbsentPresent Present Present Present Second outer middle sipes Absent PresentPresent Present Present Positional relation between First outer —independent smoothly smoothly smoothly shoulder sipes and First outermiddle sipes from each other connected connected connected Positionalrelation between First outer — independent smoothly smoothly smoothlyshoulder sipes and second outer middle sipes from each other connectedconnected connected Length L1/Length L2 [%] 83 67 67 40 40 LengthL3/Length L2 [%] — 59 59 59 59 Length L4/Length L5 [%] — 51 51 51 51Drainage performance [index] 110  95 100 80 90 Noise performance [index]90 100 100 110 105 Steering stability performance [index] 90 95 100 110105 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Outer shoulder lateral grooves PresentPresent Present Present Present First outer shoulder sipes PresentPresent Present Present Present Second outer shoulder sipes PresentPresent Present Present Present Outer middle lateral grooves AbsentAbsent Absent Absent Absent First outer middle sipes Present PresentPresent Present Present Second outer middle sipes Present PresentPresent Present Present Positional relation between First outer smoothlysmoothly smoothly smoothly smoothly shoulder sipes and First outermiddle sipes connected connected connected connected connectedPositional relation between First outer smoothly smoothly smoothlysmoothly smoothly shoulder sipes and second outer middle sipes connectedconnected connected connected connected Length L1/Length L2 [%] 75 85 6767 75 Length L3/Length L2 [%] 59 59 20 30 75 Length L4/Length L5 [%] 5151 51 51 51 Drainage performance [index] 110 120 90 95 105 Noiseperformance [index] 95 90 105 102 98 Steering stability performance[index] 95 90 105 103 97 Ex. 9 Ex. 10 Ex. 11 Ex. 12 Ex. 13 Outershoulder lateral grooves Present Present Present Present Present Firstouter shoulder sipes Present Present Present Present Present Secondouter shoulder sipes Present Present Present Present Present Outermiddle lateral grooves Absent Absent Absent Absent Absent First outermiddle sipes Present Present Present Present Present Second outer middlesipes Present Present Present Present Present Positional relationbetween First outer smoothly smoothly smoothly smoothly smoothlyshoulder sipes and First outer middle sipes connected connectedconnected connected connected Positional relation between First outersmoothly smoothly smoothly smoothly smoothly shoulder sipes and secondouter middle sipes connected connected connected connected connectedLength L1/Length L2 [%] 85 67 67 67 67 Length L3/Length L2 [%] 85 59 5959 59 Length L4/Length L5 [%] 51 25 35 70 80 Drainage performance[index] 110 90 95 105 110 Noise performance [index] 95 105 102 98 95Steering stability performance [index] 95 105 103 97 95

Pneumatic tyres of size 215/60R16 having the basic tread pattern shownin FIG. 1 were made by way of test according to the specificationslisted in Table 2, and then the test tyres were tested for the drainageperformance, the noise performance, and the steering stabilityperformance. Reference 3 was a pneumatic tyre having the tread patterndisclosed in the Patent Literature 1. The test methods were as follows.

<Drainage Performance>

The above-described test vehicle with the above-described test tyresmounted on all wheels thereof was driven on the above-described testcourse, then the average lateral G was calculated by the same method asdescribed above (lateral hydroplaning test). The test results areindicated by an index based on Example 14 being 100, wherein a largernumerical value is better.

<Noise Performance>

The sound pressure level was measured by the same method as describedabove. The test results are indicated by an index based on the Example14 being 100, wherein a larger numerical value is better.

<Steering Stability Performance>

By the same method as described above, the characteristics relating tothe grip performance, the steering response, and the responsiveness wereevaluated by the driver's feeling. The test results are indicated by anevaluation point based on the Example 14 being 100, wherein a largernumerical value shows better steering stability performance.

TABLE 2 Ref. 3 Ref. 4 Ex. 14 Ex. 15 Ex. 16 First inner middle lateralgrooves Present Present Present Present Present First inner middlelateral sipes Absent Present Present Present Present Second inner middlelateral grooves Present Present Present Present Present Second innermiddle lateral sipes Absent Present Present Present Present LengthL6/Length L7 [%] 100 40 67 50 67 Length L6/Length L7 [%] 100 40 67 67 50Length L9/Length L6 [%] — 23 23 23 23 Third inner middle lateral sipesPresent Present Present Present Present First chamfered portion PresentPresent Present Present Present Second chamfered portion Present PresentPresent Present Present Drainage performance [index] 110 80 100  85 85Noise performance [index]  90 105  100  105  105  Steering stabilityperformance [index]  90 105  100  105  105  Ex. 17 Ex. 18 Ex. 19 Ex. 20Ex. 21 First inner middle lateral grooves Present Present PresentPresent Present First inner middle lateral sipes Present Present PresentPresent Present Second inner middle lateral grooves Present PresentPresent Present Present Second inner middle lateral sipes PresentPresent Present Present Present Length L6/Length L7 [%] 67 67 67 67 67Length L6/Length L7 [%] 67 67 67 67 67 Length L9/Length L6 [%] 10 15 3540 23 Third inner middle lateral sipes Present Present Present PresentAbsent First chamfered portion Present Present Present Present PresentSecond chamfered portion Present Present Present Present PresentDrainage performance [index] 95 97 103  105  97 Noise performance[index] 102  100  98 98 100  Steering stability performance [index] 102 102  98 96 102  Ex. 21 Ex. 22 First inner middle lateral grooves PresentPresent First inner middle lateral sipes Present Present Second innermiddle lateral grooves Present Present Second inner middle lateral sipesPresent Present Length L6/Length L7 [%] 67 67 Length L6/Length L7 [%] 6767 Length L9/Length L6 [%] 23 23 Third inner middle lateral sipesPresent Present First chamfered portion Absent Present Second chamferedportion Present Absent Drainage performance [index] 97 97 Noiseperformance [index] 100  100  Steering stability performance [index]102  102 

As is clear from Table 1 and Table 2, it was confirmed that the drainageperformance, the noise performance, and the steering stabilityperformance of the tyres as the Examples were significantly improved ina good balance, as compared with the tyres as the References.

1. A tyre comprising a tread portion comprising: a first tread groundcontact edge positioned on one side of a tyre equator, a second treadground contact edge positioned on the other side of the tyre equator, afirst shoulder main groove extending continuously in a tyrecircumferential direction on a side of the first tread ground contactedge, a first crown main groove extending continuously in the tyrecircumferential direction between the first shoulder main groove and thetyre equator, a first middle land region defined between the firstshoulder main groove and the first crown main groove, and a firstshoulder land region defined between the first tread ground contact edgeand the first shoulder main groove, wherein the first shoulder landregion is provided with a plurality of first shoulder lateral grooveseach extending inwardly in a tyre axial direction from the first treadground contact edge to have a first inner end in the tyre axialdirection within the first shoulder land region, first shoulder lateralsipes each connecting between the first inner end of a respective one ofthe first shoulder lateral grooves and the first shoulder main groove,and a plurality of second shoulder lateral sipes each extending inwardlyin the tyre axial direction from the first tread ground contact edge tohave a second inner end on an outer side in the tyre axial direction ofthe first inner end, the first middle land region is provided with aplurality of middle lateral sipes each smoothly connected with arespective one of the first shoulder lateral sipes with the firstshoulder main groove therebetween, and the middle lateral sipes includefirst middle lateral sipes each connecting between the first shouldermain groove and the first crown main groove and second middle lateralsipes each having a third inner end within the first middle land region.2. The tyre according to claim 1, wherein each of the second shoulderlateral sipes is arranged between the first shoulder lateral groovesadjacent to each other in the tyre circumferential direction.
 3. Thetyre according to claim 1, wherein a length in the tyre axial directionof each of the first shoulder lateral grooves is in a range of from 50%to 75% of a length in the tyre axial direction of the first shoulderland region.
 4. The tyre according to claim 1, wherein an angle of eachof the first shoulder lateral grooves with respect to the tyre axialdirection is in a range of from 5 to 12 degrees.
 5. The tyre accordingto claim 1, wherein an angle of each of the middle lateral sipes withrespect to the tyre axial direction is in a range of from 5 to 35degrees.
 6. The tyre according to claim 1, wherein a length in the tyreaxial direction of each of the second shoulder lateral sipes is in arange of from 30% to 75% of a length in the tyre axial direction of thefirst shoulder land region.
 7. The tyre according to claim 1, wherein alength in the tyre axial direction of each of the second middle lateralsipes is in a range of from 35% to 70% of a length in the tyre axialdirection of the first middle land region.
 8. The tyre according toclaim 1 further comprising: a second shoulder main groove extendingcontinuously in the tyre circumferential direction on a side of thesecond tread ground contact edge, a second crown main groove extendingcontinuously in the tyre circumferential direction between the secondshoulder main groove and the tyre equator, and a second middle landregion defined between the second shoulder main groove and the secondcrown main groove, wherein the second middle land region is providedwith a plurality of first middle lateral grooves each extending inwardlyin the tyre axial direction from the second shoulder main groove to havea fourth inner end in the tyre axial direction within the second middleland region, third middle lateral sipes each connecting between thefourth inner end of a respective one of the first middle lateral groovesand the second crown main groove, a plurality of second middle lateralgrooves each extending inwardly in the tyre axial direction from thesecond shoulder main groove to have a fifth inner end in the tyre axialdirection within the second middle land region, and fourth middlelateral sipes each extending inwardly in the tyre axial direction fromthe fifth inner end of a respective one of the second middle lateralgrooves to have a sixth inner end in the tyre axial direction within thesecond middle land region, and a length in the tyre axial direction ofeach of the second middle lateral grooves is 50% or more of a length inthe tyre axial direction of the second middle land region.
 9. The tyreaccording to claim 8, wherein each of the second middle lateral groovesare provided between the first middle lateral grooves adjacent to eachother in the tyre circumferential direction.
 10. The tyre according toclaim 8, wherein a length in the tyre axial direction of each of thefirst middle lateral grooves is 50% or more of a length in the tyreaxial direction of the second middle land region.
 11. The tyre accordingto claim 8, wherein each of fifth middle lateral sipes is providedbetween a respective one of pairs of the first inner middle lateralgroove and the second inner middle lateral groove adjacent to each otherin the tyre circumferential direction, and each of the fifth middlelateral sipes extends inwardly in the tyre axial direction from thesecond shoulder main groove to have a seventh inner end in the tyreaxial direction within the second middle land region.
 12. The tyreaccording to claim 8, wherein the first middle lateral grooves and thesecond middle lateral grooves are inclined in the same direction withrespect to the tyre axial direction.
 13. The tyre according to claim 8,wherein a length in the tyre axial direction of each of the first middlelateral grooves is in a range of from 60% to 80% of a length in the tyreaxial direction of the second middle land region.
 14. The tyre accordingto claim 8, wherein the tread portion is provided with a second shoulderland region defined between the second tread ground contact edge and thesecond shoulder main groove, and the second shoulder land region isprovided with a plurality of second shoulder lateral grooves eachextending inwardly in the tyre axial direction from the second treadground contact edge to have a eighth inner end in the tyre axialdirection within the second shoulder land region, and third shoulderlateral sipes each connecting between the eighth inner end of arespective one of the second shoulder lateral grooves and the secondshoulder main groove.
 15. The tyre according to claim 14, wherein alength in the tyre axial direction of each of the second shoulderlateral grooves is 50% or more of a length in the tyre axial directionof the second shoulder land region.
 16. The tyre according to claim 14,wherein an angle of each of the second shoulder lateral grooves withrespect to the tyre axial direction is in a range of from 5 to 12degrees.
 17. The tyre according to claim 14, wherein the tread portionis provided with a plurality of fourth shoulder lateral sipes eachconnecting between the second tread ground contact edge and the secondshoulder main groove, and each of the fourth shoulder lateral sipes isarranged between a respective pair of the second shoulder lateralgrooves adjacent to each other in the tyre circumferential direction.18. The tyre according to claim 1, wherein a groove width of the firstshoulder main groove is smaller than a groove width of the first crownmain groove.
 19. The tyre according to claim 8, wherein a groove widthof the first shoulder main groove is smaller than a groove width of thesecond shoulder main groove and a groove width of the second crown maingroove.
 20. The tyre according to claim 1, wherein when the tyre ismounted on a vehicle, the first tread ground contact edge is an outertread ground contact edge positioned on an outer side of the vehicle.